The present disclosure relates to the field of structural systems for buildings and, more particularly, to joist seats.
Large scale, multi-story buildings are typically constructed of steel and concrete. Floors in such buildings may be constructed by spanning wide flange beams or steel joists between structural supports and installing metal decking across the tops of such beams or joists. The decking forms a horizontal surface onto which concrete is placed. Generally, the bottoms of the beams or joists form the framework from which ceilings are hung. Flooring system designs must also be mindful of fire safety, acoustics, and vibration considerations.
In some prior systems, steel joists have been assembled with joist shoes fastened to the end of the joists, such that the joist and joist shoe were supported on a structural support such as a beam. The joists and joist shoes have generally been formed from angles, and when assembled, formed a generally I-beam shaped end to the joist. In some installations, the assembled joist and joist shoe were fastened to the top of the support structure, and a floor formed above the joist. In these configurations, the height of the joist and the joist shoe added to the height and weight of the building on each floor to maintain overall floor system height. While joist and deck floor systems have been designed in the past to address one or more of these issues individually, these prior designs are not optimized and integrated with the portions of the support structure of a building to provide an integrated design to address the above-mentioned issues in a systematic manner.
Presently disclosed is a joist support system comprising a joist having joist seat at least at one end, each joist seat comprising a main steel plate having a first portion fastened to an upper chord of the joist and a second portion adapted to engage a support structure and support the joist and a bearing load, and a second steel plate welded to the main steel plate and extending downwardly from the main steel plate between the first and second portions, the second steel plate fastened with an upward support portion to an end portion of the joist extending inwardly adapted to resist transfer load on the joist seat, and a support structure adapted to support the one end of the joist by a portion of the joist seat.
The joist support system may also have the end portion of the joist to which the second steel plate is fastened comprising a joist shoe positioned below and extending inwardly from the end of the joist to a second web member adapted to resist transfer loads on the joist seat. An opening may be provided in the main steel plate adapted to permit welding on a web member of the joist through the opening. The main steel plate may be capable of being fastened to the upper chord and the second steel plate may be capable of being fastened to the joist shoe or to the end portion of the joist after the joist is positioned. The second steel plate may include an L-shaped portion adapted to upwardly engage the end portion of the joist. Further, the main steel plate may be fastened to the support structure by self-aligning fasteners, and the support structure may be a support structure comprising cold formed metal studs, a masonry wall, a cementitious wall, a metal beam, a metal truss, or other supporting structures.
Also disclosed is a joist support system comprising a joist having joist seat at least at one end, each joist seat comprising a main steel plate having a first portion welded to an upper chord of the joist and a second portion adapted to engage a support structure and support the joist and a bearing load, and a second steel plate welded to the main steel plate and extending downwardly from the main steel plate between the first and second portions, the second steel plate welded with a lateral weld portion and an upward weld portion to an end portion of the joist extending inwardly to resist transfer load on the joist seat, and a support structure adapted to support the one end of the joist by a portion of the joist seat.
The joist support system may also have the end portion of the joist to which the second steel plate is fastened comprising a joist shoe positioned below the upper chord positioned adjacent at least one end of the joist, and with the second steel plate welded with a lateral weld portion and an upward weld portion to the joist shoe extending inwardly to resist transfer load on the joist seat. Additionally, the joist shoe may extend at least slightly beyond the end of the upper chord, and each joist shoe may comprise a pair of spaced apart inward facing L-shaped members with a web of the joist positioned there between extending inwardly along the upper chord to resist transfer load on the joist seat. The main steel plate may be pre-bent downwardly prior to applying a load to the joist such that the main steel plate moves to provide more support area with the support structure when the joist is loaded. The joist support system may also include corrugated decking supported by a plurality of the joist positioned laterally, with the decking extending over the main steel plate of the joist, and a cementitious slab placed over the corrugated decking. In another example, the joist support system may further include a plurality of stand-off fasteners positioned along the joist and coupled through the decking into the upper chord of the joist and extending above the decking, and a cementitious slab placed over the corrugated decking and encapsulating the stand-off fasteners. The stand-off fasteners may be positioned along the joist with spacing between stand-off fasteners greater at center portions of the joist than at the end of the joist adjacent to joist seat.
Also disclosed is a method of constructing a joist support system comprising assembling a joist seat comprising a main steel plate having a first portion adapted to fasten to an upper chord of the joist and a second portion adapted to engage a support structure and support the joist and bearing a load, and a second steel plate welded to the main steel plate and extending downwardly from the main steel plate between the first and second portions, fastening the joist seat to an end portion of a joist with the main steel plate fastened to the upper chord of the joist and the second steel plate fastened with a lateral portion and an upwardly extending support portion to the end portion of the joist adapted to resist transfer load on the joist seat, and positioning the joist with the second portion of the joist seat engaging a support structure adapted to support the end portion of the joist by a portion of the joist seat.
The method of constructing a joist support system may also include the joist seat being directly or indirectly fastened to the upper chord of the joist. The end portion of the joist may extend inwardly from the end of the joist to a second web member adapted to resist transfer loads on the joist seat. The method may also include positioning a plurality of said assembled joists in a lateral array with a joist seat at the end portions of each joist supported on the support structure, assembling a corrugated decking supported by the plurality of the positioned joist with the decking extending over the main steel plate of the joist, and placing a cementitious slab over the corrugated decking. Additionally, the method may further include, prior to placing a cementitious slab, positioning a plurality of stand-off fasteners along the joist and coupled through the decking into the upper chord of the joist and extending above the decking such that when the cementitious slab is placed over the corrugated decking a portion of each stand-off fastener is encapsulated in the cementitious slab. The stand-off fasteners may be positioned along the joist with spacing between stand-off fasteners greater at center portions of the joist than at the end portions of the joist adjacent to joist seat.
Also disclosed is a method of constructing a joist support system comprising assembling a joist seat comprising a main steel plate having a first portion adapted to weld to an upper chord of the joist and a second portion adapted to engage a support structure and support the joist and bearing a load, and a second steel plate welded to the main steel plate and extending downwardly from the main steel plate between the first and second portions, welding the joist seat by the first portion to an end portion of a joist with the main steel plate welded to the upper chord of the joist and the second steel plate welded with a lateral weld portion and an upwardly extending weld portion to the end portion of the joist adapted to extend inwardly from the end of the joist to resist transfer load on the joist seat, and positioning the joist with the second portion of the joist seat engaging a support structure adapted to support the end portion of the joist by a portion of the joist seat.
Also disclosed is a method of constructing a joist support system comprising assembling a joist seat comprising a main steel plate having a first portion adapted to weld to an upper chord of the joist and a second portion adapted to engage a support structure and support the joist and bearing a load, and a second steel plate welded to the main steel plate and extending downwardly from the main steel plate between the first and second portions to engage the end portion of a joist shoe extending inwardly below the upper chord adapted to resist transfer loads on the joist seat, welding the joist seat by the first portion of the main steel plate to the upper chord of the joist and the second steel plate welded to end portions of the joist shoe adapted to resist transfer load on the joist seat, and positioning the joist with a second portion of the joist seat engaging a support structure adapted to support the one end portion of the joist by a portion of the joist seat.
The method of constructing a joist system may also include where the joist shoe is comprised of two abutting L-shaped members spaced apart by a web member, and the abutting L-shaped members may be positioned adjacent the upper chord of the joist in an arrangement selected from the group consisting of toe-to-toe, overlapping, or gapped. The method of constructing a joist system may further include positioning at least two assembled joists with their joist seats engaging the support structure and extending in opposite directions from the support structure, and connecting the main steel plates of the joist seats of the joists extending in opposite directions from the support structure. Additionally, the method may include assembling a corrugated decking supported by the plurality of the positioned joists with the decking extending over the main steel plates of the joists extending in opposite directions and the connection there between, and placing a cementitious slab over the corrugated decking.
The features, functions, and advantages that have been discussed maybe achieved independently in various embodiments of the present invention or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings but are not limited to only these applications shown.